(a) Field of the Invention
This invention relates to a method for the removal of polymerization heat upon production of a polymer by polymerizing one or more monomers, and more specifically to a method for controlling such polymerization heat by cooling and condensing steam occurred in a reactor.
(b) Prior Art of the Invention
It is extremely important to maintain the polymerization temperature at a predetermined level by removing polymerization heat which occurs during a polymerization reaction. It has been known to remove such polymerization heat through the wall of a reactor or by means of a heat exchanger provided inside the reactor. Since the above methods do not allow to establish a large heat transfer area in the case of a large reactor, it has also been proposed to employ a reflux condenser which makes use of latent heat of a liquid medium. It has been disclosed in Japanese Patent Publication No. 45961/1983 that a reflux condenser features large cooling capacity and can remove polymerization heat with good responsiveness if certain specific control variables are employed.
Even if the above-described method is used, it is technically difficult to control the polymerization temperature constant by changing the flow rate of a cooling medium because the quantity of heat which must be removed by a reflux condenser is enormous in a large reactor. It has been extremely difficult to solve this problem even if a special design is elaborated to provide several cooling medium flow lines having different flow rates and to control the flow rate(s) of the cooling medium through flow line(s) having smaller flow rates to cope with small variations in the quantity of heat to be removed.